{"title":"Twinning mediated anisotropic fracture behavior in bioimplant grade hot-rolled pure magnesium","authors":"Prakash C. Gautam, Somjeet Biswas","doi":"10.1016/j.jma.2024.09.013","DOIUrl":null,"url":null,"abstract":"Bioimplant grade hot-rolled magnesium with equiaxed microstructure and basal texture was examined for fracture toughness (FT) anisotropy using fatigue pre-cracked single-edge notch bending specimens with the notch, <em>a<sub>n</sub></em> ∥, ⊥ and 45° to rolling direction (RD). Due to adequate crack-tip plasticity, the size-independent elastic-plastic fracture toughness (<em>J<sub>IC</sub></em>) were determined. Anisotropic <em>J<sub>IC</sub></em> was observed due to different twin lamellae formation w.r.t. notch owing to the initial basal texture with <span><span style=\"\"></span><span data-mathml='<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow is=\"true\"><mo is=\"true\">{</mo><mrow is=\"true\"><mn is=\"true\">10</mn><mover accent=\"true\" is=\"true\"><mn is=\"true\">1</mn><mo is=\"true\">&#xAF;</mo></mover><mn is=\"true\">0</mn></mrow><mo is=\"true\">}</mo></mrow></math>' role=\"presentation\" style=\"font-size: 90%; display: inline-block; position: relative;\" tabindex=\"0\"><svg aria-hidden=\"true\" focusable=\"false\" height=\"2.779ex\" role=\"img\" style=\"vertical-align: -0.812ex;\" viewbox=\"0 -846.5 3073 1196.3\" width=\"7.137ex\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g fill=\"currentColor\" stroke=\"currentColor\" stroke-width=\"0\" transform=\"matrix(1 0 0 -1 0 0)\"><g is=\"true\"><use is=\"true\" xlink:href=\"#MJMAIN-7B\"></use><g is=\"true\" transform=\"translate(500,0)\"><g is=\"true\"><use xlink:href=\"#MJMAIN-31\"></use><use x=\"500\" xlink:href=\"#MJMAIN-30\" y=\"0\"></use></g><g is=\"true\" transform=\"translate(1001,0)\"><g is=\"true\" transform=\"translate(35,0)\"><use xlink:href=\"#MJMAIN-31\"></use></g><g is=\"true\" transform=\"translate(0,198)\"><use x=\"-70\" xlink:href=\"#MJMAIN-AF\" y=\"0\"></use><use x=\"70\" xlink:href=\"#MJMAIN-AF\" y=\"0\"></use></g></g><g is=\"true\" transform=\"translate(1571,0)\"><use xlink:href=\"#MJMAIN-30\"></use></g></g><use is=\"true\" x=\"2572\" xlink:href=\"#MJMAIN-7D\" y=\"0\"></use></g></g></svg><span role=\"presentation\"><math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow is=\"true\"><mo is=\"true\">{</mo><mrow is=\"true\"><mn is=\"true\">10</mn><mover accent=\"true\" is=\"true\"><mn is=\"true\">1</mn><mo is=\"true\">¯</mo></mover><mn is=\"true\">0</mn></mrow><mo is=\"true\">}</mo></mrow></math></span></span><script type=\"math/mml\"><math><mrow is=\"true\"><mo is=\"true\">{</mo><mrow is=\"true\"><mn is=\"true\">10</mn><mover accent=\"true\" is=\"true\"><mn is=\"true\">1</mn><mo is=\"true\">¯</mo></mover><mn is=\"true\">0</mn></mrow><mo is=\"true\">}</mo></mrow></math></script></span> and <span><span style=\"\"></span><span data-mathml='<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow is=\"true\"><mo is=\"true\">{</mo><mrow is=\"true\"><mn is=\"true\">11</mn><mover accent=\"true\" is=\"true\"><mn is=\"true\">2</mn><mo is=\"true\">&#xAF;</mo></mover><mn is=\"true\">0</mn></mrow><mo is=\"true\">}</mo></mrow></math>' role=\"presentation\" style=\"font-size: 90%; display: inline-block; position: relative;\" tabindex=\"0\"><svg aria-hidden=\"true\" focusable=\"false\" height=\"2.779ex\" role=\"img\" style=\"vertical-align: -0.812ex;\" viewbox=\"0 -846.5 3073 1196.3\" width=\"7.137ex\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g fill=\"currentColor\" stroke=\"currentColor\" stroke-width=\"0\" transform=\"matrix(1 0 0 -1 0 0)\"><g is=\"true\"><use is=\"true\" xlink:href=\"#MJMAIN-7B\"></use><g is=\"true\" transform=\"translate(500,0)\"><g is=\"true\"><use xlink:href=\"#MJMAIN-31\"></use><use x=\"500\" xlink:href=\"#MJMAIN-31\" y=\"0\"></use></g><g is=\"true\" transform=\"translate(1001,0)\"><g is=\"true\" transform=\"translate(35,0)\"><use xlink:href=\"#MJMAIN-32\"></use></g><g is=\"true\" transform=\"translate(0,198)\"><use x=\"-70\" xlink:href=\"#MJMAIN-AF\" y=\"0\"></use><use x=\"70\" xlink:href=\"#MJMAIN-AF\" y=\"0\"></use></g></g><g is=\"true\" transform=\"translate(1571,0)\"><use xlink:href=\"#MJMAIN-30\"></use></g></g><use is=\"true\" x=\"2572\" xlink:href=\"#MJMAIN-7D\" y=\"0\"></use></g></g></svg><span role=\"presentation\"><math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow is=\"true\"><mo is=\"true\">{</mo><mrow is=\"true\"><mn is=\"true\">11</mn><mover accent=\"true\" is=\"true\"><mn is=\"true\">2</mn><mo is=\"true\">¯</mo></mover><mn is=\"true\">0</mn></mrow><mo is=\"true\">}</mo></mrow></math></span></span><script type=\"math/mml\"><math><mrow is=\"true\"><mo is=\"true\">{</mo><mrow is=\"true\"><mn is=\"true\">11</mn><mover accent=\"true\" is=\"true\"><mn is=\"true\">2</mn><mo is=\"true\">¯</mo></mover><mn is=\"true\">0</mn></mrow><mo is=\"true\">}</mo></mrow></math></script></span> poles mostly ∥ and ⊥ to RD. The out-of-plane tensile stresses activated the <span><span style=\"\"></span><span data-mathml='<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow is=\"true\"><mrow is=\"true\"><mo is=\"true\">{</mo><mrow is=\"true\"><mn is=\"true\">10</mn><mover accent=\"true\" is=\"true\"><mn is=\"true\">1</mn><mo is=\"true\">&#xAF;</mo></mover><mn is=\"true\">2</mn></mrow><mo is=\"true\">}</mo></mrow><mrow is=\"true\"><mo is=\"true\">&#x3008;</mo><mrow is=\"true\"><mn is=\"true\">10</mn><mover accent=\"true\" is=\"true\"><mn is=\"true\">1</mn><mo is=\"true\">&#xAF;</mo></mover><mn is=\"true\">1</mn></mrow><mo is=\"true\">&#x3009;</mo></mrow></mrow></math>' role=\"presentation\" style=\"font-size: 90%; display: inline-block; position: relative;\" tabindex=\"0\"><svg aria-hidden=\"true\" focusable=\"false\" height=\"2.779ex\" role=\"img\" style=\"vertical-align: -0.812ex;\" viewbox=\"0 -846.5 6090.7 1196.3\" width=\"14.146ex\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g fill=\"currentColor\" stroke=\"currentColor\" stroke-width=\"0\" transform=\"matrix(1 0 0 -1 0 0)\"><g is=\"true\"><g is=\"true\"><use is=\"true\" xlink:href=\"#MJMAIN-7B\"></use><g is=\"true\" transform=\"translate(500,0)\"><g is=\"true\"><use xlink:href=\"#MJMAIN-31\"></use><use x=\"500\" xlink:href=\"#MJMAIN-30\" y=\"0\"></use></g><g is=\"true\" transform=\"translate(1001,0)\"><g is=\"true\" transform=\"translate(35,0)\"><use xlink:href=\"#MJMAIN-31\"></use></g><g is=\"true\" transform=\"translate(0,198)\"><use x=\"-70\" xlink:href=\"#MJMAIN-AF\" y=\"0\"></use><use x=\"70\" xlink:href=\"#MJMAIN-AF\" y=\"0\"></use></g></g><g is=\"true\" transform=\"translate(1571,0)\"><use xlink:href=\"#MJMAIN-32\"></use></g></g><use is=\"true\" x=\"2572\" xlink:href=\"#MJMAIN-7D\" y=\"0\"></use></g><g is=\"true\" transform=\"translate(3239,0)\"><use is=\"true\" xlink:href=\"#MJMAIN-27E8\"></use><g is=\"true\" transform=\"translate(389,0)\"><g is=\"true\"><use xlink:href=\"#MJMAIN-31\"></use><use x=\"500\" xlink:href=\"#MJMAIN-30\" y=\"0\"></use></g><g is=\"true\" transform=\"translate(1001,0)\"><g is=\"true\" transform=\"translate(35,0)\"><use xlink:href=\"#MJMAIN-31\"></use></g><g is=\"true\" transform=\"translate(0,198)\"><use x=\"-70\" xlink:href=\"#MJMAIN-AF\" y=\"0\"></use><use x=\"70\" xlink:href=\"#MJMAIN-AF\" y=\"0\"></use></g></g><g is=\"true\" transform=\"translate(1571,0)\"><use xlink:href=\"#MJMAIN-31\"></use></g></g><use is=\"true\" x=\"2461\" xlink:href=\"#MJMAIN-27E9\" y=\"0\"></use></g></g></g></svg><span role=\"presentation\"><math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow is=\"true\"><mrow is=\"true\"><mo is=\"true\">{</mo><mrow is=\"true\"><mn is=\"true\">10</mn><mover accent=\"true\" is=\"true\"><mn is=\"true\">1</mn><mo is=\"true\">¯</mo></mover><mn is=\"true\">2</mn></mrow><mo is=\"true\">}</mo></mrow><mrow is=\"true\"><mo is=\"true\">〈</mo><mrow is=\"true\"><mn is=\"true\">10</mn><mover accent=\"true\" is=\"true\"><mn is=\"true\">1</mn><mo is=\"true\">¯</mo></mover><mn is=\"true\">1</mn></mrow><mo is=\"true\">〉</mo></mrow></mrow></math></span></span><script type=\"math/mml\"><math><mrow is=\"true\"><mrow is=\"true\"><mo is=\"true\">{</mo><mrow is=\"true\"><mn is=\"true\">10</mn><mover accent=\"true\" is=\"true\"><mn is=\"true\">1</mn><mo is=\"true\">¯</mo></mover><mn is=\"true\">2</mn></mrow><mo is=\"true\">}</mo></mrow><mrow is=\"true\"><mo is=\"true\">〈</mo><mrow is=\"true\"><mn is=\"true\">10</mn><mover accent=\"true\" is=\"true\"><mn is=\"true\">1</mn><mo is=\"true\">¯</mo></mover><mn is=\"true\">1</mn></mrow><mo is=\"true\">〉</mo></mrow></mrow></math></script></span> extension twins (ET) as usual with matrix-ET Σ15b coincident site lattice boundary (CSLB) interfaces. While the in-plane tensile stress ⊥ to the crack-tip activated <span><span style=\"\"></span><span data-mathml='<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow is=\"true\"><mrow is=\"true\"><mo is=\"true\">{</mo><mrow is=\"true\"><mn is=\"true\">10</mn><mover accent=\"true\" is=\"true\"><mn is=\"true\">1</mn><mo is=\"true\">&#xAF;</mo></mover><mn is=\"true\">1</mn></mrow><mo is=\"true\">}</mo></mrow><mrow is=\"true\"><mo is=\"true\">&#x3008;</mo><mrow is=\"true\"><mn is=\"true\">10</mn><mover accent=\"true\" is=\"true\"><mn is=\"true\">1</mn><mo is=\"true\">&#xAF;</mo></mover><mn is=\"true\">2</mn></mrow><mo is=\"true\">&#x3009;</mo></mrow></mrow></math>' role=\"presentation\" style=\"font-size: 90%; display: inline-block; position: relative;\" tabindex=\"0\"><svg aria-hidden=\"true\" focusable=\"false\" height=\"2.779ex\" role=\"img\" style=\"vertical-align: -0.812ex;\" viewbox=\"0 -846.5 6090.7 1196.3\" width=\"14.146ex\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g fill=\"currentColor\" stroke=\"currentColor\" stroke-width=\"0\" transform=\"matrix(1 0 0 -1 0 0)\"><g is=\"true\"><g is=\"true\"><use is=\"true\" xlink:href=\"#MJMAIN-7B\"></use><g is=\"true\" transform=\"translate(500,0)\"><g is=\"true\"><use xlink:href=\"#MJMAIN-31\"></use><use x=\"500\" xlink:href=\"#MJMAIN-30\" y=\"0\"></use></g><g is=\"true\" transform=\"translate(1001,0)\"><g is=\"true\" transform=\"translate(35,0)\"><use xlink:href=\"#MJMAIN-31\"></use></g><g is=\"true\" transform=\"translate(0,198)\"><use x=\"-70\" xlink:href=\"#MJMAIN-AF\" y=\"0\"></use><use x=\"70\" xlink:href=\"#MJMAIN-AF\" y=\"0\"></use></g></g><g is=\"true\" transform=\"translate(1571,0)\"><use xlink:href=\"#MJMAIN-31\"></use></g></g><use is=\"true\" x=\"2572\" xlink:href=\"#MJMAIN-7D\" y=\"0\"></use></g><g is=\"true\" transform=\"translate(3239,0)\"><use is=\"true\" xlink:href=\"#MJMAIN-27E8\"></use><g is=\"true\" transform=\"translate(389,0)\"><g is=\"true\"><use xlink:href=\"#MJMAIN-31\"></use><use x=\"500\" xlink:href=\"#MJMAIN-30\" y=\"0\"></use></g><g is=\"true\" transform=\"translate(1001,0)\"><g is=\"true\" transform=\"translate(35,0)\"><use xlink:href=\"#MJMAIN-31\"></use></g><g is=\"true\" transform=\"translate(0,198)\"><use x=\"-70\" xlink:href=\"#MJMAIN-AF\" y=\"0\"></use><use x=\"70\" xlink:href=\"#MJMAIN-AF\" y=\"0\"></use></g></g><g is=\"true\" transform=\"translate(1571,0)\"><use xlink:href=\"#MJMAIN-32\"></use></g></g><use is=\"true\" x=\"2461\" xlink:href=\"#MJMAIN-27E9\" y=\"0\"></use></g></g></g></svg><span role=\"presentation\"><math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow is=\"true\"><mrow is=\"true\"><mo is=\"true\">{</mo><mrow is=\"true\"><mn is=\"true\">10</mn><mover accent=\"true\" is=\"true\"><mn is=\"true\">1</mn><mo is=\"true\">¯</mo></mover><mn is=\"true\">1</mn></mrow><mo is=\"true\">}</mo></mrow><mrow is=\"true\"><mo is=\"true\">〈</mo><mrow is=\"true\"><mn is=\"true\">10</mn><mover accent=\"true\" is=\"true\"><mn is=\"true\">1</mn><mo is=\"true\">¯</mo></mover><mn is=\"true\">2</mn></mrow><mo is=\"true\">〉</mo></mrow></mrow></math></span></span><script type=\"math/mml\"><math><mrow is=\"true\"><mrow is=\"true\"><mo is=\"true\">{</mo><mrow is=\"true\"><mn is=\"true\">10</mn><mover accent=\"true\" is=\"true\"><mn is=\"true\">1</mn><mo is=\"true\">¯</mo></mover><mn is=\"true\">1</mn></mrow><mo is=\"true\">}</mo></mrow><mrow is=\"true\"><mo is=\"true\">〈</mo><mrow is=\"true\"><mn is=\"true\">10</mn><mover accent=\"true\" is=\"true\"><mn is=\"true\">1</mn><mo is=\"true\">¯</mo></mover><mn is=\"true\">2</mn></mrow><mo is=\"true\">〉</mo></mrow></mrow></math></script></span> contraction twins (CT) that transform into <span><span style=\"\"></span><span data-mathml='<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow is=\"true\"><mo is=\"true\">{</mo><mrow is=\"true\"><mn is=\"true\">10</mn><mover accent=\"true\" is=\"true\"><mn is=\"true\">1</mn><mo is=\"true\">&#xAF;</mo></mover><mn is=\"true\">1</mn></mrow><mo is=\"true\">}</mo></mrow></math>' role=\"presentation\" style=\"font-size: 90%; display: inline-block; position: relative;\" tabindex=\"0\"><svg aria-hidden=\"true\" focusable=\"false\" height=\"2.779ex\" role=\"img\" style=\"vertical-align: -0.812ex;\" viewbox=\"0 -846.5 3073 1196.3\" width=\"7.137ex\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g fill=\"currentColor\" stroke=\"currentColor\" stroke-width=\"0\" transform=\"matrix(1 0 0 -1 0 0)\"><g is=\"true\"><use is=\"true\" xlink:href=\"#MJMAIN-7B\"></use><g is=\"true\" transform=\"translate(500,0)\"><g is=\"true\"><use xlink:href=\"#MJMAIN-31\"></use><use x=\"500\" xlink:href=\"#MJMAIN-30\" y=\"0\"></use></g><g is=\"true\" transform=\"translate(1001,0)\"><g is=\"true\" transform=\"translate(35,0)\"><use xlink:href=\"#MJMAIN-31\"></use></g><g is=\"true\" transform=\"translate(0,198)\"><use x=\"-70\" xlink:href=\"#MJMAIN-AF\" y=\"0\"></use><use x=\"70\" xlink:href=\"#MJMAIN-AF\" y=\"0\"></use></g></g><g is=\"true\" transform=\"translate(1571,0)\"><use xlink:href=\"#MJMAIN-31\"></use></g></g><use is=\"true\" x=\"2572\" xlink:href=\"#MJMAIN-7D\" y=\"0\"></use></g></g></svg><span role=\"presentation\"><math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow is=\"true\"><mo is=\"true\">{</mo><mrow is=\"true\"><mn is=\"true\">10</mn><mover accent=\"true\" is=\"true\"><mn is=\"true\">1</mn><mo is=\"true\">¯</mo></mover><mn is=\"true\">1</mn></mrow><mo is=\"true\">}</mo></mrow></math></span></span><script type=\"math/mml\"><math><mrow is=\"true\"><mo is=\"true\">{</mo><mrow is=\"true\"><mn is=\"true\">10</mn><mover accent=\"true\" is=\"true\"><mn is=\"true\">1</mn><mo is=\"true\">¯</mo></mover><mn is=\"true\">1</mn></mrow><mo is=\"true\">}</mo></mrow></math></script></span>-<span><span style=\"\"></span><span data-mathml='<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow is=\"true\"><mo is=\"true\">{</mo><mrow is=\"true\"><mn is=\"true\">10</mn><mover accent=\"true\" is=\"true\"><mn is=\"true\">1</mn><mo is=\"true\">&#xAF;</mo></mover><mn is=\"true\">2</mn></mrow><mo is=\"true\">}</mo></mrow></math>' role=\"presentation\" style=\"font-size: 90%; display: inline-block; position: relative;\" tabindex=\"0\"><svg aria-hidden=\"true\" focusable=\"false\" height=\"2.779ex\" role=\"img\" style=\"vertical-align: -0.812ex;\" viewbox=\"0 -846.5 3073 1196.3\" width=\"7.137ex\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g fill=\"currentColor\" stroke=\"currentColor\" stroke-width=\"0\" transform=\"matrix(1 0 0 -1 0 0)\"><g is=\"true\"><use is=\"true\" xlink:href=\"#MJMAIN-7B\"></use><g is=\"true\" transform=\"translate(500,0)\"><g is=\"true\"><use xlink:href=\"#MJMAIN-31\"></use><use x=\"500\" xlink:href=\"#MJMAIN-30\" y=\"0\"></use></g><g is=\"true\" transform=\"translate(1001,0)\"><g is=\"true\" transform=\"translate(35,0)\"><use xlink:href=\"#MJMAIN-31\"></use></g><g is=\"true\" transform=\"translate(0,198)\"><use x=\"-70\" xlink:href=\"#MJMAIN-AF\" y=\"0\"></use><use x=\"70\" xlink:href=\"#MJMAIN-AF\" y=\"0\"></use></g></g><g is=\"true\" transform=\"translate(1571,0)\"><use xlink:href=\"#MJMAIN-32\"></use></g></g><use is=\"true\" x=\"2572\" xlink:href=\"#MJMAIN-7D\" y=\"0\"></use></g></g></svg><span role=\"presentation\"><math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow is=\"true\"><mo is=\"true\">{</mo><mrow is=\"true\"><mn is=\"true\">10</mn><mover accent=\"true\" is=\"true\"><mn is=\"true\">1</mn><mo is=\"true\">¯</mo></mover><mn is=\"true\">2</mn></mrow><mo is=\"true\">}</mo></mrow></math></span></span><script type=\"math/mml\"><math><mrow is=\"true\"><mo is=\"true\">{</mo><mrow is=\"true\"><mn is=\"true\">10</mn><mover accent=\"true\" is=\"true\"><mn is=\"true\">1</mn><mo is=\"true\">¯</mo></mover><mn is=\"true\">2</mn></mrow><mo is=\"true\">}</mo></mrow></math></script></span> double twins (DT) with matrix-DT Σ23b and Σ15a CSLBs. For <em>a<sub>n</sub></em>∥ RD, large DT lamellae fraction formed at ∼30° and few ETs at ∼30° and ∼90° to the notch with crack growth mainly via the Σ23b/Σ15a CSLB interfaces during FT. While, significant DT and ET lamellae developed at ∼0° and ∼60° with cracking via the matrix-DT Σ23b/Σ15a and matrix-ET Σ15b CSLBs for <em>a<sub>n</sub></em>⊥ RD. The DT and ET lamellae activated at ∼15°, and the crack propagated through Σ15b for <span><span style=\"\"></span><span data-mathml='<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow is=\"true\"><msub is=\"true\"><mi is=\"true\">a</mi><mi is=\"true\">n</mi></msub><mo is=\"true\">&#x223C;</mo><msup is=\"true\"><mrow is=\"true\"><mn is=\"true\">45</mn></mrow><mo is=\"true\">&#x2218;</mo></msup></mrow></math>' role=\"presentation\" style=\"font-size: 90%; display: inline-block; position: relative;\" tabindex=\"0\"><svg aria-hidden=\"true\" focusable=\"false\" height=\"2.432ex\" role=\"img\" style=\"vertical-align: -0.582ex;\" viewbox=\"0 -796.9 3843.1 1047.3\" width=\"8.926ex\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g fill=\"currentColor\" stroke=\"currentColor\" stroke-width=\"0\" transform=\"matrix(1 0 0 -1 0 0)\"><g is=\"true\"><g is=\"true\"><g is=\"true\"><use xlink:href=\"#MJMATHI-61\"></use></g><g is=\"true\" transform=\"translate(529,-150)\"><use transform=\"scale(0.707)\" xlink:href=\"#MJMATHI-6E\"></use></g></g><g is=\"true\" transform=\"translate(1331,0)\"><use xlink:href=\"#MJMAIN-223C\"></use></g><g is=\"true\" transform=\"translate(2388,0)\"><g is=\"true\"><g is=\"true\"><use xlink:href=\"#MJMAIN-34\"></use><use x=\"500\" xlink:href=\"#MJMAIN-35\" y=\"0\"></use></g></g><g is=\"true\" transform=\"translate(1001,404)\"><use transform=\"scale(0.707)\" xlink:href=\"#MJMAIN-2218\"></use></g></g></g></g></svg><span role=\"presentation\"><math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow is=\"true\"><msub is=\"true\"><mi is=\"true\">a</mi><mi is=\"true\">n</mi></msub><mo is=\"true\">∼</mo><msup is=\"true\"><mrow is=\"true\"><mn is=\"true\">45</mn></mrow><mo is=\"true\">∘</mo></msup></mrow></math></span></span><script type=\"math/mml\"><math><mrow is=\"true\"><msub is=\"true\"><mi is=\"true\">a</mi><mi is=\"true\">n</mi></msub><mo is=\"true\">∼</mo><msup is=\"true\"><mrow is=\"true\"><mn is=\"true\">45</mn></mrow><mo is=\"true\">∘</mo></msup></mrow></math></script></span> to RD. The <em>J<sub>IC</sub></em> and the crack-tip plastic zone decreases, while the elastic component of the J-integral (<em>J<sub>el</sub></em>) and the ET formation increases from <em>a<sub>n</sub></em>∥, ⊥, to <span><span style=\"\"></span><span data-mathml='<math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow is=\"true\"><mo is=\"true\">&#x223C;</mo><msup is=\"true\"><mn is=\"true\">45</mn><mo is=\"true\">&#x2218;</mo></msup></mrow></math>' role=\"presentation\" style=\"font-size: 90%; display: inline-block; position: relative;\" tabindex=\"0\"><svg aria-hidden=\"true\" focusable=\"false\" height=\"2.086ex\" role=\"img\" style=\"vertical-align: -0.235ex;\" viewbox=\"0 -796.9 2511.2 898.2\" width=\"5.832ex\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g fill=\"currentColor\" stroke=\"currentColor\" stroke-width=\"0\" transform=\"matrix(1 0 0 -1 0 0)\"><g is=\"true\"><g is=\"true\"><use xlink:href=\"#MJMAIN-223C\"></use></g><g is=\"true\" transform=\"translate(1056,0)\"><g is=\"true\"><use xlink:href=\"#MJMAIN-34\"></use><use x=\"500\" xlink:href=\"#MJMAIN-35\" y=\"0\"></use></g><g is=\"true\" transform=\"translate(1001,404)\"><use transform=\"scale(0.707)\" xlink:href=\"#MJMAIN-2218\"></use></g></g></g></g></svg><span role=\"presentation\"><math xmlns=\"http://www.w3.org/1998/Math/MathML\"><mrow is=\"true\"><mo is=\"true\">∼</mo><msup is=\"true\"><mn is=\"true\">45</mn><mo is=\"true\">∘</mo></msup></mrow></math></span></span><script type=\"math/mml\"><math><mrow is=\"true\"><mo is=\"true\">∼</mo><msup is=\"true\"><mn is=\"true\">45</mn><mo is=\"true\">∘</mo></msup></mrow></math></script></span> to RD. The strain incompatibility of matrices was higher with the geometrically hard ETs than DTs. Thus, brittle interlamellar cracking occurred through the Σ15b interfaces. In contrast, almost similar and higher crack-tip plasticity occurred in matrix and DT domains during crack propagation via Σ23b/Σ15a CSLBs. Crack growth through Σ23b/Σ15a led to high <em>J<sub>IC</sub></em>, both Σ15b and Σ23b/Σ15a led to moderate <em>J<sub>IC</sub></em>, and Σ15b least <em>J<sub>IC</sub></em> for <em>a<sub>n</sub></em> ∥, ⊥ and 45° to RD, respectively.","PeriodicalId":16214,"journal":{"name":"Journal of Magnesium and Alloys","volume":null,"pages":null},"PeriodicalIF":15.8000,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Magnesium and Alloys","FirstCategoryId":"88","ListUrlMain":"https://doi.org/10.1016/j.jma.2024.09.013","RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"METALLURGY & METALLURGICAL ENGINEERING","Score":null,"Total":0}
引用次数: 0
Abstract
Bioimplant grade hot-rolled magnesium with equiaxed microstructure and basal texture was examined for fracture toughness (FT) anisotropy using fatigue pre-cracked single-edge notch bending specimens with the notch, an ∥, ⊥ and 45° to rolling direction (RD). Due to adequate crack-tip plasticity, the size-independent elastic-plastic fracture toughness (JIC) were determined. Anisotropic JIC was observed due to different twin lamellae formation w.r.t. notch owing to the initial basal texture with and poles mostly ∥ and ⊥ to RD. The out-of-plane tensile stresses activated the extension twins (ET) as usual with matrix-ET Σ15b coincident site lattice boundary (CSLB) interfaces. While the in-plane tensile stress ⊥ to the crack-tip activated contraction twins (CT) that transform into - double twins (DT) with matrix-DT Σ23b and Σ15a CSLBs. For an∥ RD, large DT lamellae fraction formed at ∼30° and few ETs at ∼30° and ∼90° to the notch with crack growth mainly via the Σ23b/Σ15a CSLB interfaces during FT. While, significant DT and ET lamellae developed at ∼0° and ∼60° with cracking via the matrix-DT Σ23b/Σ15a and matrix-ET Σ15b CSLBs for an⊥ RD. The DT and ET lamellae activated at ∼15°, and the crack propagated through Σ15b for to RD. The JIC and the crack-tip plastic zone decreases, while the elastic component of the J-integral (Jel) and the ET formation increases from an∥, ⊥, to to RD. The strain incompatibility of matrices was higher with the geometrically hard ETs than DTs. Thus, brittle interlamellar cracking occurred through the Σ15b interfaces. In contrast, almost similar and higher crack-tip plasticity occurred in matrix and DT domains during crack propagation via Σ23b/Σ15a CSLBs. Crack growth through Σ23b/Σ15a led to high JIC, both Σ15b and Σ23b/Σ15a led to moderate JIC, and Σ15b least JIC for an ∥, ⊥ and 45° to RD, respectively.
期刊介绍:
The Journal of Magnesium and Alloys serves as a global platform for both theoretical and experimental studies in magnesium science and engineering. It welcomes submissions investigating various scientific and engineering factors impacting the metallurgy, processing, microstructure, properties, and applications of magnesium and alloys. The journal covers all aspects of magnesium and alloy research, including raw materials, alloy casting, extrusion and deformation, corrosion and surface treatment, joining and machining, simulation and modeling, microstructure evolution and mechanical properties, new alloy development, magnesium-based composites, bio-materials and energy materials, applications, and recycling.